Manufacturing method of semiconductor substrate and semiconductor device

ABSTRACT

Provided is a highly integrated semiconductor device, a semiconductor device with large storage capacitance with respect to an area occupied by a capacitor, a semiconductor device capable of high-speed writing or reading, a semiconductor device with low power consumption, or a highly reliable semiconductor device. Provided are steps of forming a first oxide semiconductor over a first substrate, forming a first insulator over the first oxide semiconductor, injecting an ion into a region of the first oxide semiconductor through the first insulator, bonding a surface of the first insulator provided with the first substrate to a surface of a second insulator over a second substrate, performing a heat treatment in a state where the surfaces are bonded, separating the first substrate from the second substrate along the region of the first oxide semiconductor, and forming a second oxide semiconductor over the second substrate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an object, a method, or a manufacturing method. The present invention relates to a process, a machine, manufacture, or a composition of matter. In particular, the present invention relates to a semiconductor, a semiconductor device, a display device, a light-emitting device, a lighting device, a power storage device, a memory device, or a processor. The present invention relates to a manufacturing method of a semiconductor, a semiconductor device, a display device, a light-emitting device, a lighting device, a power storage device, a memory device, or a processor. The present invention relates to a driving method of a semiconductor device, a display device, a light-emitting device, a lighting device, a power storage device, a memory device, or a processor.

In this specification and the like, a semiconductor device generally means a device that can function by utilizing semiconductor characteristics. A display device, a light-emitting device, a lighting device, an electro-optical device, a semiconductor circuit, and an electronic device include a semiconductor device in some cases.

2. Description of the Related Art

In recent years, a metal oxide showing semiconductor characteristics called an oxide semiconductor has attracted attention as a novel semiconductor material for a transistor.

A transistor using the oxide semiconductor has a good feature of very smaller off-state current than a transistor using silicon. To make use of this feature, a semiconductor device including a transistor using the oxide semiconductor and a transistor using a semiconductor other than the oxide semiconductor, such as silicon, has been developed.

Although a substrate used for forming a semiconductor layer is necessary in the fabrication process of the semiconductor device, it sometimes limits the performance and usage of the semiconductor device. For this reason, a method of separating a transistor and a semiconductor layer from the substrate has been developed.

REFERENCE Patent Document [Patent Document 1] Japanese Published Patent Application No. 2009-88497 [Patent Document 2] Japanese Published Patent Application No. 2013-243216 SUMMARY OF THE INVENTION

An object of the present invention is to provide a substrate having a single crystal oxide semiconductor. Another object is to provide a highly integrated semiconductor device. Another object is to provide a semiconductor device with large storage capacitance with respect to an area occupied by a capacitor. Another object is to provide a semiconductor device capable of high-speed writing. Another object is to provide a semiconductor device capable of high-speed reading. Another object is to provide a semiconductor device with low power consumption. Another object of the present invention is to provide a highly reliable semiconductor device. Another object is to provide a novel semiconductor device.

Note that the descriptions of these objects do not disturb the existence of other objects. In one embodiment of the present invention, there is no need to achieve all the objects. Other objects will be apparent from and can be derived from the description of the specification, the drawings, the claims, and the like.

(1) One embodiment of the present invention is a manufacturing method of a semiconductor substrate including steps of forming a first oxide semiconductor over a first substrate, forming a first insulator over the first oxide semiconductor, injecting an ion into a region of the first oxide semiconductor through the first insulator, bonding a surface of the first insulator provided with the first substrate to a surface of a second insulator provided with a second substrate, performing a heat treatment in a state where the surfaces are bonded, separating the first substrate from the second substrate along the region of the first oxide semiconductor, and forming a second oxide semiconductor over the second substrate.

(2) One embodiment of the present invention is the manufacturing method of a semiconductor substrate, described in (1), in which the first oxide semiconductor has a single crystal structure.

(3) One embodiment of the present invention is the manufacturing method of a semiconductor substrate, described in (1) or (2), in which the ion is a hydrogen ion.

(4) One embodiment of the present invention is the manufacturing method of a semiconductor substrate, described in any one of (1) to (3), in which the bonding is performed by combining the surface of the first insulator with the surface of the second insulator.

(5) One embodiment of the present invention is a manufacturing method of a semiconductor substrate including steps of forming a first oxide semiconductor over a first substrate, forming a first insulator over the first oxide semiconductor, injecting an ion into a region of the first oxide semiconductor through the first insulator, bonding a surface of the first insulator provided with the first substrate to a surface of a second insulator over a second substrate, the second substrate comprising a semiconductor element and the second insulator over the semiconductor element, performing a heat treatment in a state where the surfaces are bonded, separating the first substrate from the second substrate along the region of the first oxide semiconductor, and obtaining a second oxide semiconductor and the semiconductor element over the second substrate.

(6) One embodiment of the present invention is a manufacturing method of a semiconductor substrate including steps of forming a first oxide semiconductor over a first substrate, forming a first insulator over the first oxide semiconductor, injecting an ion into a region of the first oxide semiconductor through the first insulator, bonding a surface of the first insulator provided with the first substrate to a surface of a second insulator over a second substrate, performing a heat treatment in a state where the surfaces are bonded, separating the first substrate from the second substrate along the region of the first oxide semiconductor, forming a second oxide semiconductor over the second substrate, and obtaining a semiconductor element including the second oxide semiconductor.

(7) One embodiment of the present invention is a manufacturing method of a semiconductor substrate including steps of forming a first oxide semiconductor over a first substrate, forming a first insulator over the first oxide semiconductor, injecting an ion into a region of the first oxide semiconductor through the first insulator, bonding a surface of the first insulator provided with the first substrate to a surface of a second insulator over a second substrate, the second substrate comprising a first semiconductor element and the second insulator over the first semiconductor element, performing a heat treatment in a state where the surfaces are bonded, separating the first substrate from the second substrate along the region of the first oxide semiconductor, forming a second oxide semiconductor and the first semiconductor element over the second substrate, and obtaining a second semiconductor element including the second oxide semiconductor.

(8) One embodiment of the present invention is the manufacturing method of a semiconductor substrate, described in any one of (5) to (7), in which the first oxide semiconductor has a single crystal structure.

(9) One embodiment of the present invention is the manufacturing method of a semiconductor substrate, described in any one of (5) to (8), in which the ion is a hydrogen ion.

(10) One embodiment of the present invention is the manufacturing method of a semiconductor substrate, described in any one of (5) to (9), in which the bonding is performed by combining the surface of the first insulator with the surface of the second insulator.

A substrate having a single crystal oxide semiconductor can be provided. A highly integrated semiconductor device can be provided. A semiconductor device with large storage capacitance with respect to an area occupied by a capacitor can be provided. A semiconductor device capable of high-speed writing can be provided. A semiconductor device capable of high-speed reading can be provided. A semiconductor device with low power consumption can be provided. Furthermore, a highly reliable semiconductor device can be provided. A novel semiconductor device can be provided.

Note that the description of these effects does not disturb the existence of other effects. One embodiment of the present invention does not necessarily achieve all the objects listed above. Other effects will be apparent from and can be derived from the description of the specification, the drawings, the claims, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a semiconductor substrate of one embodiment of the present invention.

FIGS. 2A to 2C are cross-sectional view illustrating a manufacturing method of a semiconductor substrate of one embodiment of the present invention.

FIGS. 3A to 3B are cross-sectional views illustrating a manufacturing method of a semiconductor substrate of one embodiment of the present invention.

FIGS. 4A and 4B are cross-sectional views illustrating a manufacturing method of a semiconductor substrate of one embodiment of the present invention.

FIGS. 5A and 5B are cross-sectional views illustrating a manufacturing method of a semiconductor device of one embodiment of the present invention.

FIGS. 6A and 6B are cross-sectional views illustrating a manufacturing method of a semiconductor device of one embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a manufacturing method of a semiconductor device of one embodiment of the present invention.

FIGS. 8A and 8B are circuit diagrams of semiconductor devices of a semiconductor device of one embodiment of the present invention.

FIGS. 9A and 9B are circuit diagrams of a memory device of one embodiment of the present invention.

FIG. 10 is a block diagram illustrating an RF tag of one embodiment of the present invention.

FIGS. 11A to 11F illustrate application examples of an RF tag of one embodiment of the present invention.

FIG. 12 is a block diagram illustrating a CPU of one embodiment of the present invention.

FIG. 13 is a circuit diagram of a memory element of one embodiment of the present invention.

FIGS. 14A to 14C are circuit diagrams of a display device of one embodiment of the present invention.

FIG. 15 illustrates a display module of one embodiment of the present invention.

FIGS. 16A to 16F illustrate electronic devices of one embodiment of the present invention.

FIGS. 17A1 to 17A3, 17B1 and 17B2, and 17C1 and C2 illustrate electronic devices of one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiment of the present invention will be described in detail with the reference to the drawings. However, the present invention is not limited to the description below, and it is easily understood by those skilled in the art that modes and details disclosed herein can be modified in various ways. The present invention is not construed as being limited to description of the embodiments and the examples. In describing structures of the present invention with reference to the drawings, common reference numerals are used for the same portions in different drawings. Note that the same hatched pattern is applied to similar parts, and the similar parts are not especially denoted by reference numerals in some cases.

The size, the thickness of films (layers), or regions in drawings is sometimes exaggerated for simplicity.

A voltage usually refers to a potential difference between a given potential and a reference potential (e.g., a source potential or a ground potential (GND)). A voltage can be referred to as a potential and vice versa.

Note that the ordinal numbers such as “first” and “second” in this specification are used for convenience and do not denote the order of steps or the stacking order of layers. Therefore, for example, description can be made even when “first” is replaced with “second” or “third”, as appropriate. The ordinal numbers in this specification and the like are not necessarily the same as those which specify one embodiment of the present invention.

Note that an impurity in a semiconductor refers to, for example, elements other than the main components of the semiconductor. For example, an element with a concentration of lower than 0.1 atomic % is an impurity. When an impurity is contained, the density of states (DOS) may be formed in a semiconductor, the carrier mobility may be decreased, or the crystallinity may be decreased, for example. In the case where the semiconductor is an oxide semiconductor, examples of an impurity which changes characteristics of the semiconductor include Group 1 elements, Group 2 elements, Group 14 elements, Group 15 elements, and transition metals other than the main components; specifically, there are hydrogen (included in water), lithium, sodium, silicon, boron, phosphorus, carbon, and nitrogen, for example. In the case of an oxide semiconductor, oxygen vacancy may be formed by entry of impurities such as hydrogen. Further, in the case where the semiconductor is silicon, examples of an impurity which changes characteristics of the semiconductor include oxygen, Group 1 elements except hydrogen, Group 2 elements, Group 13 elements, and Group 15 elements.

Note that in the embodiments described below, an insulator may be formed to have, for example, a single-layer structure or a stacked-layer structure including an insulator containing one or more of boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum, neodymium, hafnium, and tantalum unless otherwise specified. A resin may be used as the insulator. For example, a resin containing polyimide, polyamide, acrylic, silicone, or the like may be used. The use of a resin does not need planarization treatment performed on a top surface of the insulator in some cases. The use of resin enables a thick film to be formed in a short time; thus, the productivity can be increased. The insulator may be preferably formed to have a single-layer structure or a stacked-layer structure including an insulator containing aluminum oxide, silicon nitride oxide, silicon nitride, gallium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, or tantalum oxide.

In the embodiments described below, a conductor may be formed to have, for example, a single-layer structure or a stacked-layer structure including a conductor containing one or more of boron, nitrogen, oxygen, fluorine, silicon, phosphorus, aluminum, titanium, chromium, manganese, cobalt, nickel, copper, zinc, gallium, yttrium, zirconium, molybdenum, ruthenium, silver, indium, tin, tantalum, and tungsten unless otherwise specified. An alloy film or a compound film of the above element may be used, for example, and a conductor containing aluminum, a conductor containing copper and titanium, a conductor containing copper and manganese, a conductor containing indium, tin, and oxygen, a conductor containing titanium and nitrogen, or the like may be used.

In this specification, the phrase “A has a region with a concentration B” includes, for example, the case where the concentration of the whole of a region of A in the depth direction is B, the case where the average concentration in a region of A in the depth direction is B, the case where the median value of a concentration in a region of A in the depth direction is B, the case where the maximum value of a concentration in a region of A in the depth direction is B, the case where the minimum value of a concentration in a region of A in the depth direction is B, the case where a convergence value of a concentration in a region of A in the depth direction is B, and the case where a concentration in a region in which a probable value of A is obtained in measurement is B.

In this specification, the phrase “A has a region with a size B, a length B, a thickness B, a width B, or a distance B” includes, for example, the case where the whole of a region of A has a size B, a length B, a thickness B, a width B, or a distance B, the case where the average value in a region of A has a size B, a length B, a thickness B, a width B, or a distance B, the case where the median value in a region of A has a size B, a length B, a thickness B, a width B, or a distance B, the case where the maximum value in a region of A has a size B, a length B, a thickness B, a width B, or a distance B, the case where the minimum value in a region of A has a size B, a length B, a thickness B, a width B, or a distance B, the case where a convergence value in a region of A has a size B, a length B, a thickness B, a width B, or a distance B, and the case where a region in which a probable value of A is obtained in measurement has a size B, a length B, a thickness B, a width B, or a distance B″.

Note that the terms “film” and “layer” can be interchanged with each other depending on the case or circumstances. For example, the term “conductive layer” can be changed into the term “conductive film” in some cases. Also, the term “insulating film” can be changed into the term “insulating layer” in some cases.

Embodiment 1

Embodiment 1 describes a manufacturing method of a semiconductor substrate in which a substrate having a single crystal semiconductor or a single crystal semiconductor substrate is bonded to another substrate (see FIG. 1).

A single crystal oxide semiconductor substrate can be used as a substrate 300 shown in FIG. 2A. A material having resistance high enough to withstand heat at least in a later heating step is used for the substrate 300. For example, an yttria-stabilized zirconia (YSZ) substrate, a sapphire substrate, a quartz substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, and a gallium oxide substrate can be used.

It is preferable to use a single crystal substrate whose formation surface is a particular crystal plane as the substrate 300. This is because a crystal part in an oxide semiconductor formed later can have high orientation in an a-b plane direction, and energy required for rearrangement of atoms in heat treatment can be reduced, leading to low-temperature formation of a single crystal oxide semiconductor. A single crystal oxide semiconductor with high characteristics can thus be formed.

The oxide semiconductor is formed (see FIG. 2A). A CAAC-OS (C Axis Aligned Crystalline Oxide Semiconductor) is formed by sputtering with an In—Ga—Zn-oxide target (atomic ratio of In:Ga:Zn=1:1:5) for example, while heating the substrate at a treatment temperature from 150° C. to 400° C., preferably 300° C. to 400° C. Chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), atomic layer deposition (ALD), or the like may be used for forming the oxide semiconductor.

In the case where an In—Ga—Zn-oxide is formed by metal organic chemical vapor deposition (MOCVD), trimethylindium, trimethylgallium, dimethylzinc, and the like can be used as a source gas. The source gas is not limited to the combination of these gases, and triethylindium or the like may be used instead of trimethylindium. Triethylgallium or the like may be used instead of trimethylgallium. Diethylzinc or the like may be used instead of dimethylzinc.

The oxide semiconductor is then crystallized. In the case where a diffusion furnace is used, the oxide semiconductor is heated at a treatment temperature from 800 to 1400° C., preferably 800 to 1300° C., further preferably 800 to 1200° C., in an oxygen atmosphere for 1 to 5 hours, for example.

When a rapid thermal anneal (RTA) apparatus is alternatively used for the heating, the oxide semiconductor can be heated near a substrate strain point or at a slightly higher temperature.

Alternatively, laser light irradiation may be used for the crystallization. For example, a continuous-wave laser (a CW laser) and a pulsed laser (the repetition rate of which is from 10 to 100 MHz is preferable) can be used. Specific examples of the continuous wave laser include an Ar laser, a Kr laser, a CO₂ laser, a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃ laser, a GdVO₄ laser, a Y₂O₃ laser, a ruby laser, an Alexandrite laser, a Ti:sapphire laser, and a helium cadmium laser. Specific examples of the pulsed laser include an Ar laser, a Kr laser, an excimer (ArF, KrF, or XeCl) laser, a CO₂ laser, a YAG laser, a YVO₄ laser, a YLF laser, a YAlO₃ laser, a GdVO₄ laser, a Y₂O₃ laser, a ruby laser, an Alexandrite laser, a Ti:sapphire laser, a copper vapor laser, and a gold vapor laser.

An insulator 301 is formed over a single crystal oxide semiconductor 306 which is formed by the crystallization of the oxide semiconductor (see FIG. 2A). The insulator 301 is formed by sputtering, CVD, ALD, or the like.

Then, ion is implanted to a region 310 in the single crystal oxide semiconductor 306 through the insulator 301 (see FIG. 2B), whereby pores are formed in the region 310 (see FIG. 2C). As a source gas used in this ion implantation, a hydrogen gas, an inert gas, or a halogen gas can be used. In the case of using a hydrogen gas, ion species of H⁺ and H₃ ⁺ can be generated. More H₃ ⁺ is preferably injected when the hydrogen gas is used as the source gas. This is because ion implantation efficiency is more improved i.e., the implantation time can be shortened, than the case where H⁺ or H₂ ⁺ is implanted.

An inert gas, such as a helium gas, may be mixed with a hydrogen gas or may be used alone. Alternatively, a halogen gas, such as a fluorine gas, may be used. The ion implantation is performed using an ion doping apparatus or an ion implanter.

Another substrate 400 is prepared next. A glass substrate, an yttria-stabilized zirconia (YSZ) substrate, a sapphire substrate, a quartz substrate, a silicon substrate, a carbide silicon substrate, a gallium nitride substrate, a gallium oxide substrate, or the like can be used as the substrate 400.

An insulator 401 is formed over the substrate 400. The insulator 401 can be formed by sputtering, CVD, MBE, PLD, ALD, or the like.

The single crystal oxide semiconductor over the substrate 300 is transferred to the substrate 400.

The surface of the insulator 301, which is on the lowermost of the substrate 300, is bonded to the surface of the insulator 401, which is on the uppermost of the substrate 400, whereby the surface of the insulator 301 is weakly combined with the surface of the insulator 401 (see FIGS. 3A and 3B). Then, heat treatment is performed at 400 to 700° C., preferably 500 to 600° C., whereby these surfaces are more strongly combined. Furthermore, inner pressure of the pores in the region 310 in the single crystal oxide semiconductor 306 is increased, and the single crystal oxide semiconductor 306 is divided into single crystal oxide semiconductors 306 a and 306 b in the region 310. The single crystal oxide semiconductor 306 b is consequently formed on the surface of the substrate 400 (see FIG. 4A).

In the case of using a single crystal oxide semiconductor substrate as the substrate 300, heat treatment and laser light irradiation for the single crystallization can be omitted.

The surface of the single crystal oxide semiconductor 306 b over the substrate 400 is planarized by chemical mechanical polishing (CMP). Other treatment may be used instead of CMP. Etching (dry etching or wet etching), plasma treatment, or the like and CMP may be combined. In this manner, the substrate 400 having the single crystal oxide semiconductor 306 b can be fabricated (see FIG. 4B).

Another method will be described. The insulator 301 is formed over the single crystal oxide semiconductor 306 on the substrate 300 and is bonded to the insulator 401 over the substrate 400, whereby the surfaces of the insulators 401 and 301 are bonded weakly. Heat treatment is then performed at 400 to 700° C., preferably 500 to 600° C., whereby these surfaces are bonded more strongly.

After that, polishing is performed on the top surface of the overturned substrate 300 toward the surface of the single crystal oxide semiconductor 306 by mechanical polishing (MP) and/or chemical mechanical polishing (CMP). In this manner, the substrate 400 having the single crystal oxide semiconductor 306 b is obtained.

Embodiment 2

In Embodiment 2, a manufacturing method of a semiconductor substrate including a process of bonding a substrate having a single crystal semiconductor or a single crystal semiconductor substrate to another substrate including a semiconductor element is described.

The substrate 400 is prepared. For example an yttria-stabilized zirconia (YSZ) substrate, a sapphire substrate, a quartz substrate, a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, or a gallium oxide substrate can be used as the substrate 400.

A semiconductor element region 425 is formed in the substrate 400 (see FIG. 5A). First, a transistor 500 is formed in the substrate 400. The structure of the transistor 500 is not limited to FIG. 5A, and the substrate 400 may have a projection (also referred to as a protrusion or a fin).

An insulator 411 is formed over the transistor 500 by sputtering, CVD, MBE, PLD, ALD, or the like. The surface of the insulator 411 is then planarized by CMP. Other treatment may be used instead of CMP. A combination of CMP and etching (dry etching or wet etching), plasma treatment, or the like may be used.

An insulator 422 may be formed over the insulator 411. The insulator 422 is preferably capable of blocking diffusion of hydrogen contained in the semiconductor element region 425 to the oxide semiconductor over the semiconductor element region 425. For example, an aluminum oxide film or a silicon nitride film may be used. The insulator 422 can be formed by sputtering, CVD, MBE, PLD, ALD, or the like.

A conductor 450 as a wiring layer may be formed over the insulator 422. The conductor 450 can be formed by sputtering, CVD, MBE, PLD, ALD, or the like. The insulator 401 is formed over the conductor 450. The insulator 401 can be formed by sputtering, CVD, MBE, PLD, ALD, or the like.

The insulator 401 is then planarized by CMP. Other treatment may be employed instead of CMP. Etching (dry etching or wet etching) or plasma treatment and CMP may be combined.

The single crystal oxide semiconductor over the substrate 300 is bonded to the substrate 400 and the single crystal oxide semiconductor is separated from the substrate 300 in the same manner as in Embodiment 1 (see FIGS. 2A to 4B).

In this manner, the semiconductor device shown in FIG. 5A including the semiconductor element region 425 and the single crystal oxide semiconductor 306 b in the substrate 400 can be fabricated.

A transistor including a single crystal oxide semiconductor has low defect density and excellent characteristics. Particularly in a memory element, off-state current of a transistor and leakage current of a capacitor are extremely small, and the area of the capacitor can be small. A semiconductor device with a small occupation area, i.e., a high integration scale can be thus provided. A transistor including a single crystal oxide semiconductor can have excellent on-state characteristics. With high on-state current in a memory element, a semiconductor device with high writing and reading rate can be provided.

Embodiment 3

A manufacturing method of a semiconductor device described in Embodiment 3 includes a process of bonding a substrate having a single crystal semiconductor or a single crystal semiconductor substrate to another substrate including a semiconductor element and a process of forming a semiconductor element including the bonded single crystal oxide semiconductor.

The manufacturing method in Embodiment 3 is similar to that in Embodiment 2 up to and including the step of forming the semiconductor device which includes the single crystal oxide semiconductor 306 b and the semiconductor element region 425 in the substrate 400 (see FIG. 5A).

A manufacturing method of a semiconductor element region 325 including the single crystal oxide semiconductor 306 b is then described. A transistor 200 including the single crystal oxide semiconductor 306 b is formed (see FIG. 5B). The capacitor 100 may be formed simultaneously. An insulator 311 is formed over the transistor 200 and the capacitor 100. The insulator 311 is preferably capable of blocking diffusion of oxygen contained in the single crystal oxide semiconductor 306 b. An aluminum oxide film or a silicon nitride film may be used. The insulator 311 can be formed by sputtering, CVD, MBE, PLD, ALD, or the like.

Next, an insulator 322 is formed over the insulator 311 (see FIG. 5B). The insulator 322 can be formed by sputtering, CVD, MBE, PLD, ALD, or the like. The insulator 322 is then planarized by CMP. Other treatment may be employed instead of CMP. CMP may be combined with etching (dry etching or wet etching), plasma treatment, or the like.

The semiconductor element region 425 is electrically connected to the semiconductor element region 325 through a contact hole. FIG. 6A shows an example in which a gate electrode of the transistor 500 in the semiconductor element region 425 is connected to a drain electrode or a source electrode of the transistor 200 in the semiconductor element region 325. A contact hole is appropriately formed so that they can be electrically connected to each other.

A conductor is preferably embedded into the contact hole. The conductor can be formed by sputtering, CVD, MBE, PLD, ALD, or the like. Then, planarization by CMP is performed on the conductor to expose the upper surface of the insulator 322. Other treatment may be employed instead of CMP. CMP may be combined with etching (dry etching or wet etching), plasma treatment, or the like.

A conductor 350 as a wiring layer is formed over the insulator 322 (see FIG. 6A). The conductor can be formed by sputtering, CVD, MBE, PLD, ALD, or the like.

In this manner, one substrate having a single crystal semiconductor or one single crystal semiconductor substrate is bonded to the other substrate 400 including the semiconductor element region 425, and the semiconductor element region 325 including the bonded single crystal oxide semiconductor 306 b is formed. As a result, the semiconductor device including the single crystal oxide semiconductor 306 b can be obtained.

In Embodiment 1, a single crystal semiconductor or a single crystal semiconductor substrate is separated and then bonded to the substrate 400. In contrast, in Embodiment 3, a single crystal semiconductor is bonded to the substrate 400 where no semiconductor element is previously formed and the semiconductor element region 325 including the single crystal oxide semiconductor 306 b is formed (see FIG. 6B).

Embodiment 4

Embodiment 4 describes a method example of forming a semiconductor element region 525 over the semiconductor device manufactured in Embodiment 3 with reference to FIG. 7.

An insulator 501 is formed over the conductor 350 by sputtering, CVD, MBE, PLD, ALD, or the like. The surface of the insulator 501 is then planarized by CMP. Other treatment may be employed instead of CMP, and CMP may be combined with etching (dry etching or wet etching), plasma treatment, or the like.

A transistor 600 including the oxide semiconductor 506 is formed over the insulator 501. The capacitor 150 may be formed simultaneously. An insulator 511 is formed over the transistor 600 and the capacitor 150. The insulator 511 is preferably capable of blocking diffusion of oxygen contained in the oxide semiconductor 506. An aluminum oxide film or a silicon nitride film may be used. The insulator 511 can be formed by sputtering, CVD, MBE, PLD, ALD, or the like.

The insulator 522 is formed over the insulator 522 by sputtering, CVD, MBE, PLD, ALD, or the like. The surface of the insulator 522 is then planarized by CMP. Other treatment may be employed instead of CMP, and CMP may be combined with etching (dry etching or wet etching), plasma treatment, or the like.

A conductor 550 as a wiring layer is then formed over the insulator 522 by sputtering, CVD, MBE, PLD, ALD, or the like.

Embodiment 4 describes an example in which the semiconductor element region 525 including an oxide semiconductor is formed over the semiconductor device manufactured in Embodiment 3. Semiconductor element regions may be further formed over the semiconductor element region 525 to manufacture a semiconductor with higher integration scale.

Embodiment 5

An example of a circuit including a transistor of one embodiment of the present invention and an example of a semiconductor device will be described.

<Circuit> [CMOS Inverter]

A circuit diagram in FIG. 8A shows a configuration of a so-called CMOS inverter circuit in which the p-channel transistor 2200 and the n-channel transistor 2100 are connected to each other in series and in which gates of them are connected to each other.

[CMOS Analog Switch]

A circuit diagram in FIG. 8B shows a configuration in which sources of the transistors 2100 and 2200 are connected to each other and drains of the transistors 2100 and 2200 are connected to each other. With such a configuration, the transistors can function as a so-called CMOS analog switch.

[Memory Device Example]

An example of a semiconductor device (memory device) which includes the transistor of one embodiment of the present invention, which can retain stored data even when not powered, and which has an unlimited number of write cycles is shown in FIGS. 9A and 9B.

The semiconductor device illustrated in FIG. 9A includes a transistor 3200 using a first semiconductor, a transistor 3300 using a second semiconductor, and a capacitor 3400. Note that any of the above-described transistors described in Embodiment 3 can be used as the transistor 3300.

The transistor 3300 is a transistor using an oxide semiconductor. Since the off-state current of the transistor 3300 is low, stored data can be retained for a long period at a predetermined node of the semiconductor device. In other words, power consumption of the semiconductor device can be reduced because refresh operation becomes unnecessary or the frequency of refresh operation can be extremely low.

In FIG. 9A, a first wiring 3001 is electrically connected to a source of the transistor 3200. A second wiring 3002 is electrically connected to a drain of the transistor 3200. A third wiring 3003 is electrically connected to one of the source and the drain of the transistor 3300. A fourth wiring 3004 is electrically connected to the gate of the transistor 3300. The gate of the transistor 3200 and the other of the source and the drain of the transistor 3300 are electrically connected to the one electrode of the capacitor 3400. A fifth wiring 3005 is electrically connected to the other electrode of the capacitor 3400.

The semiconductor device in FIG. 9A has a feature that the potential of the gate of the transistor 3200 can be retained, and thus enables writing, retaining, and reading of data as follows.

Writing and retaining of data are described. First, the potential of the fourth wiring 3004 is set to a potential at which the transistor 3300 is turned on, so that the transistor 3300 is turned on. Accordingly, the potential of the third wiring 3003 is supplied to a node FG where the gate of the transistor 3200 and the one electrode of the capacitor 3400 are electrically connected to each other. That is, a predetermined charge is supplied to the gate of the transistor 3200 (writing). Here, one of two kinds of charges providing different potential levels (hereinafter referred to as a low-level charge and a high-level charge) is supplied. After that, the potential of the fourth wiring 3004 is set to a potential at which the transistor 3300 is turned off, whereby the charge is held at the node FG (retaining).

Since the off-state current of the transistor 3300 is extremely low, the charge of the node FG is retained for a long time.

Next, reading of data is described. An appropriate potential (a reading potential) is supplied to the fifth wiring 3005 while a predetermined potential (a constant potential) is supplied to the first wiring 3001, whereby the potential of the second wiring 3002 varies depending on the amount of charge retained in the node FG.

This is because in the case of using an n-channel transistor as the transistor 3200, an apparent threshold voltage V_(th) _(—) _(H) at the time when the high-level charge is given to the gate of the transistor 3200 is lower than an apparent threshold voltage V_(th) _(—) _(L) at the time when the low-level charge is given to the gate of the transistor 3200. Here, an apparent threshold voltage refers to the potential of the fifth wiring 3005 which is needed to turn on the transistor 3200. Thus, the potential of the fifth wiring 3005 is set to a potential V₀ which is between V_(th) _(—) _(H) and V_(th) _(—) _(L), whereby charge supplied to the node FG can be determined. For example, in the case where the high-level charge is supplied to the node FG in writing and the potential of the fifth wiring 3005 is V₀ (>V_(th) _(—) _(H)), the transistor 3200 is turned on. On the other hand, in the case where the low-level charge is supplied to the node FG in writing, even when the potential of the fifth wiring 3005 is V₀ (<V_(th) _(—) _(L)), the transistor 3200 remains off. Thus, the data retained in the node FG can be read by determining the potential of the second wiring 3002.

Note that in the case where memory cells are arrayed, it is necessary that data of a desired memory cell be read in read operation. In the case where data of the other memory cells is not read, the fifth wiring 3005 may be supplied with a potential at which the transistor 3200 is turned off regardless of the charge supplied to the node FG, that is, a potential lower than V_(th) _(—) _(H). Alternatively, the fifth wiring 3005 may be supplied with a potential at which the transistor 3200 is turned on regardless of the charge supplied to the node FG, that is, a potential higher than V_(th) _(—) _(L).

The semiconductor device in FIG. 9B is different from the semiconductor device in FIG. 9A in that the transistor 3200 is not provided. Also in this case, writing and retaining operation of data can be performed in a manner similar to the semiconductor device in FIG. 9A.

Reading of data in the semiconductor device in FIG. 9B is described. When the transistor 3300 is turned on, the third wiring 3003 which is in a floating state and the capacitor 3400 are electrically connected to each other, and the charge is redistributed between the third wiring 3003 and the capacitor 3400. As a result, the potential of the third wiring 3003 is changed. The amount of change in potential of the third wiring 3003 varies depending on the potential of the one electrode of the capacitor 3400 (or the charge accumulated in the capacitor 3400).

For example, the potential of the third wiring 3003 after the charge redistribution is (C_(B)×V_(B0)+C×n/(C_(B)+C), where V is the potential of the one electrode of the capacitor 3400, C is the capacitance of the capacitor 3400, C_(B) is the capacitance component of the third wiring 3003, and V_(B0) is the potential of the third wiring 3003 before the charge redistribution. Thus, it can be found that, assuming that the memory cell is in either of two states in which the potential of a first terminal of the capacitor 3400 is V₁ and V₀ (V₁>V₀), the potential of the third wiring 3003 in the case of retaining the potential V₁(=(C_(B)×V_(B0)+C×V₁)/(C_(B)+C)) is higher than the potential of the third wiring 3003 in the case of retaining the potential V₀ (=(C_(B)×V_(B0)+C×V₀)/(C_(B)+C)).

Then, by comparing the potential of the third wiring 3003 with a predetermined potential, data can be read.

In this case, a transistor including the first semiconductor may be used for a driver circuit for driving a memory cell, and a transistor including the second semiconductor may be stacked over the driver circuit as the transistor 3300.

When including a transistor using an oxide semiconductor and having an extremely low off-state current, the semiconductor device described above can retain stored data for a long time. In other words, refresh operation becomes unnecessary or the frequency of the refresh operation can be extremely low, which leads to a sufficient reduction in power consumption. Moreover, stored data can be retained for a long time even when power is not supplied (note that a potential is preferably fixed).

Further, in the semiconductor device, high voltage is not needed for writing data and deterioration of elements is less likely to occur. Unlike in a conventional nonvolatile memory, for example, it is not necessary to inject and extract electrons into and from a floating gate; thus, a problem such as deterioration of an insulating layer is not caused. That is, the semiconductor device of one embodiment of the present invention does not have a limit on the number of times data can be rewritten, which is a problem of a conventional nonvolatile memory, and the reliability thereof is drastically improved. Furthermore, data is written depending on the state of the transistor (on or off), whereby high-speed operation can be easily achieved.

<RF Tag>

An RF tag including the transistor or the memory device is described below with reference to FIG. 10.

The RF tag of one embodiment of the present invention includes a memory circuit, stores data in the memory circuit, and transmits and receives data to/from the outside by using contactless means, for example, wireless communication. With these features, the RF tag can be used for an individual authentication system in which an object or the like is recognized by reading the individual information, for example. Note that the RF tag is required to have high reliability in order to be used for this purpose.

A configuration of the RF tag will be described with reference to FIG. 10. FIG. 10 is a block diagram illustrating a configuration example of an RF tag.

As shown in FIG. 10, an RF tag 800 includes an antenna 804 which receives a radio signal 803 that is transmitted from an antenna 802 connected to a communication device 801 (also referred to as an interrogator, a reader/writer, or the like). The RF tag 800 includes a rectifier circuit 805, a constant voltage circuit 806, a demodulation circuit 807, a modulation circuit 808, a logic circuit 809, a memory circuit 810, and a ROM 811. A semiconductor of a transistor having a rectifying function included in the demodulation circuit 807 may be a material which enables a reverse current to be low enough, for example, an oxide semiconductor. This can suppress the phenomenon of a rectifying function becoming weaker due to generation of a reverse current and prevent saturation of the output from the demodulation circuit. In other words, the input to the demodulation circuit and the output from the demodulation circuit can have a relation closer to a linear relation. Note that data transmission methods are roughly classified into the following three methods: an electromagnetic coupling method in which a pair of coils is provided so as to face each other and communicates with each other by mutual induction, an electromagnetic induction method in which communication is performed using an induction field, and a radio wave method in which communication is performed using a radio wave. Any of these methods can be used in the RF tag 800.

Next, the structure of each circuit will be described. The antenna 804 exchanges the radio signal 803 with the antenna 802 which is connected to the communication device 801. The rectifier circuit 805 generates an input potential by rectification, for example, half-wave voltage doubler rectification of an input alternating signal generated by reception of a radio signal at the antenna 804 and smoothing of the rectified signal with a capacitor provided in a later stage in the rectifier circuit 805. Note that a limiter circuit may be provided on an input side or an output side of the rectifier circuit 805. The limiter circuit controls electric power so that electric power which is higher than or equal to certain electric power is not input to a circuit in a later stage if the amplitude of the input alternating signal is high and an internal generation voltage is high.

The constant voltage circuit 806 generates a stable power supply voltage from an input potential and supplies it to each circuit. Note that the constant voltage circuit 806 may include a reset signal generation circuit. The reset signal generation circuit is a circuit that generates a reset signal of the logic circuit 809 by utilizing rise of the stable power supply voltage.

The demodulation circuit 807 demodulates the input alternating signal by envelope detection and generates the demodulated signal. Further, the modulation circuit 808 performs modulation in accordance with data to be output from the antenna 804.

The logic circuit 809 analyzes and processes the demodulated signal. The memory circuit 810 holds the input data and includes a row decoder, a column decoder, a memory region, and the like. Further, the ROM 811 stores an identification number (ID) or the like and outputs it in accordance with processing.

Note that the decision whether each circuit described above is provided or not can be made as appropriate as needed.

Here, the above-described memory device can be used as the memory circuit 810. Since the memory device of one embodiment of the present invention can retain data even when not powered, the memory device is suitable for an RF tag. Further, the memory device of one embodiment of the present invention needs power (voltage) needed for data writing lower than that needed in a conventional nonvolatile memory; thus, it is possible to prevent a difference between the maximum communication range in data reading and that in data writing. Furthermore, it is possible to suppress malfunction or incorrect writing which is caused by power shortage in data writing.

Since the memory device of one embodiment of the present invention can be used as a nonvolatile memory, it can also be used as the ROM 811. In this case, it is preferable that a manufacturer separately prepare a command for writing data to the ROM 811 so that a user cannot rewrite data freely. Since the manufacturer gives identification numbers before shipment and then starts shipment of products, instead of putting identification numbers to all the manufactured RF tags, it is possible to put identification numbers to only good products to be shipped. Thus, the identification numbers of the shipped products are in series and customer management corresponding to the shipped products is easily performed.

<Application Examples of RF Tag>

Application examples of the RF tag of one embodiment of the present invention are shown below with reference to FIGS. 11A to 11F. The RF tag is widely used and can be provided for, for example, products such as bills, coins, securities, bearer bonds, documents (e.g., driver's licenses or resident's cards, see FIG. 11A), packaging containers (e.g., wrapping paper or bottles, see FIG. 11C), recording media (e.g., DVD software or video tapes, see FIG. 11B), vehicles (e.g., bicycles, see FIG. 11D), personal belongings (e.g., bags or glasses), foods, plants, animals, human bodies, clothing, household goods, medical supplies such as medicine and chemicals, and electronic devices (e.g., liquid crystal display devices, EL display devices, television sets, or cellular phones), or tags on products (see FIGS. 11E and 11F).

An RF tag 4000 of one embodiment of the present invention is fixed on products by, for example, being attached to a surface thereof or being embedded therein. For example, the RF tag 4000 is fixed to each product by being embedded in paper of a book, or embedded in an organic resin of a package. The RF tag 4000 of one embodiment of the present invention is small, thin, and lightweight, so that the design of a product is not impaired even after the RF tag 4000 of one embodiment of the present invention is fixed thereto. Further, bills, coins, securities, bearer bonds, documents, or the like can have identification functions by being provided with the RF tag 4000 of one embodiment of the present invention, and the identification functions can be utilized to prevent counterfeits. Moreover, the efficiency of a system such as an inspection system can be improved by providing the RF tag 4000 of one embodiment of the present invention for packaging containers, recording media, personal belongings, foods, clothing, household goods, electronic devices, or the like. Vehicles can also have higher security against theft or the like by being provided with the RF tag 4000 of one embodiment of the present invention.

As described above, the RF tag of one embodiment of the present invention can be used for the above-described purposes.

<CPU>

A CPU including a semiconductor device such as any of the above-described transistors or the above-described memory device is described below.

FIG. 12 is a block diagram illustrating a configuration example of a CPU including any of the above-described transistors as a component.

The CPU illustrated in FIG. 12 includes, over a substrate 1190, an arithmetic logic unit (ALU) 1191, an ALU controller 1192, an instruction decoder 1193, an interrupt controller 1194, a timing controller 1195, a register 1196, a register controller 1197, a bus interface 1198 (Bus I/F), a rewritable ROM 1199, and an ROM interface 1189 (ROM I/F). A semiconductor substrate, an SOI substrate, a glass substrate, or the like is used as the substrate 1190. The rewritable ROM 1199 and the ROM interface 1189 may be provided over a separate chip. Needless to say, the CPU in FIG. 12 is just an example in which the configuration has been simplified, and an actual CPU may have a variety of configurations depending on the application. For example, the CPU may have the following configuration: a structure including the CPU illustrated in FIG. 12 or an arithmetic circuit is considered as one core; a plurality of the cores are included; and the cores achieve parallel operation. The number of bits that the CPU can process in an internal arithmetic circuit or in a data bus can be 8, 16, 32, or 64, for example.

An instruction that is input to the CPU through the bus interface 1198 is input to the instruction decoder 1193 and decoded therein, and then, input to the ALU controller 1192, the interrupt controller 1194, the register controller 1197, and the timing controller 1195.

The ALU controller 1192, the interrupt controller 1194, the register controller 1197, and the timing controller 1195 conduct various controls in accordance with the decoded instruction. Specifically, the ALU controller 1192 generates signals for controlling the operation of the ALU 1191. While the CPU is executing a program, the interrupt controller 1194 judges an interrupt request from an external input/output device or a peripheral circuit on the basis of its priority or a mask state, and processes the request. The register controller 1197 generates an address of the register 1196, and reads/writes data from/to the register 1196 in accordance with the state of the CPU.

In the CPU illustrated in FIG. 12, a memory cell is provided in the register 1196. For the memory cell of the register 1196, any of the above-described transistors, the above-described memory device, or the like can be used.

In the CPU illustrated in FIG. 12, the register controller 1197 selects operation of retaining data in the register 1196 in accordance with an instruction from the ALU 1191. That is, the register controller 1197 selects whether data is retained by a flip-flop or by a capacitor in the memory cell included in the register 1196. When data retaining by the flip-flop is selected, a power supply voltage is supplied to the memory cell in the register 1196. When data retaining by the capacitor is selected, the data is rewritten in the capacitor, and supply of power supply voltage to the memory cell in the register 1196 can be stopped.

FIG. 13 is an example of a circuit diagram of a memory element that can be used as the register 1196. A memory element 1200 includes a circuit 1201 in which stored data is volatile when power supply is stopped, a circuit 1202 in which stored data is nonvolatile even when power supply is stopped, a switch 1203, a switch 1204, a logic element 1206, a capacitor 1207, and a circuit 1220 having a selecting function. The circuit 1202 includes a capacitor 1208, a transistor 1209, and a transistor 1210. Note that the memory element 1200 may further include another element such as a diode, a resistor, or an inductor, as needed.

Here, the above-described memory device can be used as the circuit 1202. When supply of a power supply voltage to the memory element 1200 is stopped, GND (0 V) or a potential at which the transistor 1209 in the circuit 1202 is turned off continues to be input to a gate of the transistor 1209. For example, the gate of the transistor 1209 is grounded through a load such as a resistor.

Shown here is an example in which the switch 1203 is a transistor 1213 having one conductivity type (e.g., an n-channel transistor) and the switch 1204 is a transistor 1214 having a conductivity type opposite to the one conductivity type (e.g., a p-channel transistor). A first terminal of the switch 1203 corresponds to one of a source and a drain of the transistor 1213, a second terminal of the switch 1203 corresponds to the other of the source and the drain of the transistor 1213, and conduction or non-conduction between the first terminal and the second terminal of the switch 1203 (i.e., the on/off state of the transistor 1213) is selected by a control signal RD input to a gate of the transistor 1213. A first terminal of the switch 1204 corresponds to one of a source and a drain of the transistor 1214, a second terminal of the switch 1204 corresponds to the other of the source and the drain of the transistor 1214, and conduction or non-conduction between the first terminal and the second terminal of the switch 1204 (i.e., the on/off state of the transistor 1214) is selected by the control signal RD input to a gate of the transistor 1214.

One of a source and a drain of the transistor 1209 is electrically connected to one of a pair of electrodes of the capacitor 1208 and a gate of the transistor 1210. Here, the connection portion is referred to as a node M2. One of a source and a drain of the transistor 1210 is electrically connected to a line which can supply a low power supply potential (e.g., a GND line), and the other thereof is electrically connected to the first terminal of the switch 1203 (the one of the source and the drain of the transistor 1213). The second terminal of the switch 1203 (the other of the source and the drain of the transistor 1213) is electrically connected to the first terminal of the switch 1204 (the one of the source and the drain of the transistor 1214). The second terminal of the switch 1204 (the other of the source and the drain of the transistor 1214) is electrically connected to a line which can supply a power supply potential VDD. The second terminal of the switch 1203 (the other of the source and the drain of the transistor 1213), the first terminal of the switch 1204 (the one of the source and the drain of the transistor 1214), an input terminal of the logic element 1206, and one of a pair of electrodes of the capacitor 1207 are electrically connected to each other. Here, the connection portion is referred to as a node M1. The other of the pair of electrodes of the capacitor 1207 can be supplied with a constant potential. For example, the other of the pair of electrodes of the capacitor 1207 can be supplied with a low power supply potential (e.g., GND) or a high power supply potential (e.g., VDD). The other of the pair of electrodes of the capacitor 1207 is electrically connected to the line which can supply a low power supply potential (e.g., a GND line). The other of the pair of electrodes of the capacitor 1208 can be supplied with a constant potential. For example, the other of the pair of electrodes of the capacitor 1208 can be supplied with the low power supply potential (e.g., GND) or the high power supply potential (e.g., VDD). The other of the pair of electrodes of the capacitor 1208 is electrically connected to the line which can supply a low power supply potential (e.g., a GND line).

The capacitor 1207 and the capacitor 1208 are not necessarily provided as long as the parasitic capacitance of the transistor, the wiring, or the like is actively utilized.

A control signal WE is input to a first gate (first gate electrode) of the transistor 1209. As for each of the switch 1203 and the switch 1204, a conduction state or a non-conduction state between the first terminal and the second terminal is selected by the control signal RD which is different from the control signal WE. When the first terminal and the second terminal of one of the switches are in the conduction state, the first terminal and the second terminal of the other of the switches are in the non-conduction state.

A signal corresponding to data retained in the circuit 1201 is input to the other of the source and the drain of the transistor 1209. FIG. 13 illustrates an example in which a signal output from the circuit 1201 is input to the other of the source and the drain of the transistor 1209. The logic value of a signal output from the second terminal of the switch 1203 (the other of the source and the drain of the transistor 1213) is inverted by the logic element 1206, and the inverted signal is input to the circuit 1201 through the circuit 1220.

In the example of FIG. 13, a signal output from the second terminal of the switch 1203 (the other of the source and the drain of the transistor 1213) is input to the circuit 1201 through the logic element 1206 and the circuit 1220; however, one embodiment of the present invention is not limited thereto. The signal output from the second terminal of the switch 1203 (the other of the source and the drain of the transistor 1213) may be input to the circuit 1201 without its logic value being inverted. For example, in the case where the circuit 1201 includes a node in which a signal obtained by inversion of the logic value of a signal input from the input terminal is retained, the signal output from the second terminal of the switch 1203 (the other of the source and the drain of the transistor 1213) can be input to the node.

In FIG. 13, among the transistors used in the memory element 1200, the transistor 492 or the like may be used as the transistor 1209, for example. As the transistors other than the transistor 1209, the transistor 491 or the like may be used, for example.

As the circuit 1201 in FIG. 13, for example, a flip-flop circuit can be used. As the logic element 1206, for example, an inverter or a clocked inverter can be used.

In a period during which the memory element 1200 is not supplied with the power supply voltage, the semiconductor device of one embodiment of the present invention can retain data stored in the circuit 1201 by the capacitor 1208 which is provided in the circuit 1202.

The off-state current of a transistor in which a channel is formed in an oxide semiconductor layer is extremely low. For example, the off-state current of a transistor in which a channel is formed in an oxide semiconductor layer is significantly lower than that of a transistor in which a channel is formed in silicon having crystallinity. Thus, when the transistor is used as the transistor 1209, a signal held in the capacitor 1208 is retained for a long time also in a period during which the power supply voltage is not supplied to the memory element 1200. The memory element 1200 can accordingly retain the stored content (data) also in a period during which the supply of the power supply voltage is stopped.

Since the above-described memory element performs pre-charge operation with the switch 1203 and the switch 1204, the time required for the circuit 1201 to retain original data again after the supply of the power supply voltage is restarted can be shortened.

In the circuit 1202, a signal retained by the capacitor 1208 is input to the gate of the transistor 1210. Therefore, after supply of the power supply voltage to the memory element 1200 is restarted, the signal retained by the capacitor 1208 can be converted into the one corresponding to the state (the on state or the off state) of the transistor 1210 to be read from the circuit 1202. Consequently, an original signal can be accurately read even when a potential corresponding to the signal retained by the capacitor 1208 varies to some degree.

By applying the above-described memory element 1200 to a memory device such as a register or a cache memory included in a processor, data in the memory device can be prevented from being lost owing to the stop of the supply of the power supply voltage. Furthermore, shortly after the supply of the power supply voltage is restarted, the memory device can be returned to the same state as that before the power supply is stopped. Therefore, the power supply can be stopped even for a short time in the processor or one or a plurality of logic circuits included in the processor, resulting in lower power consumption.

Although the memory element 1200 is used in a CPU in this embodiment, the memory element 1200 can also be used in an LSI such as a digital signal processor (DSP), a custom LSI, or a programmable logic device (PLD), and a radio frequency (RF) tag.

<Display Device>

The following shows configuration examples of a display device of one embodiment of the present invention.

[Structure Example]

FIG. 14A is a top view of a display device of one embodiment of the present invention. FIG. 14B illustrates a pixel circuit where a liquid crystal element is used for a pixel of a display device of one embodiment of the present invention. FIG. 14C illustrates a pixel circuit where an organic EL element is used for a pixel of a display device of one embodiment of the present invention.

The transistor 200 or the like can be used as a transistor used for the pixel. Here, an example in which an n-channel transistor is used is shown. Note that a transistor manufactured through the same steps as the transistor used for the pixel may be used for a driver circuit. Thus, the use of the above-described transistors for a pixel or a driver circuit allows the display device to have high display quality and/or high reliability.

FIG. 14A illustrates an example of a top view of an active matrix display device. A pixel portion 5001, a first scan line driver circuit 5002, a second scan line driver circuit 5003, and a signal line driver circuit 5004 are provided over a substrate 5000 in the display device. The pixel portion 5001 is electrically connected to the signal line driver circuit 5004 through a plurality of signal lines and is electrically connected to the first scan line driver circuit 5002 and the second scan line driver circuit 5003 through a plurality of scan lines. Pixels including display elements are provided in respective regions divided by the scan lines and the signal lines. The substrate 5000 of the display device is electrically connected to a timing control circuit (also referred to as a controller or a control IC) through a connection portion such as a flexible printed circuit (FPC).

The first scan line driver circuit 5002, the second scan line driver circuit 5003, and the signal line driver circuit 5004 are formed over the substrate 5000 where the pixel portion 5001 is formed. Therefore, a display device can be manufactured at cost lower than that in the case where a driver circuit is separately formed. Furthermore, in the case where a driver circuit is separately formed, the number of wiring connections is increased. By providing the driver circuit over the substrate 5000, the number of wiring connections can be reduced. Accordingly, the reliability and/or yield can be improved.

[Liquid Crystal Display Device]

FIG. 14B illustrates an example of a circuit configuration of the pixel. Here, a pixel circuit which is applicable to a pixel of a VA liquid crystal display device, or the like is illustrated.

This pixel circuit can be applied to a structure in which one pixel includes a plurality of pixel electrodes. The pixel electrodes are connected to different transistors, and the transistors can be driven with different gate signals. Accordingly, signals applied to individual pixel electrodes in a multi-domain pixel can be controlled independently.

A gate wiring 5012 of a transistor 5016 and a gate wiring 5013 of a transistor 5017 are separated so that different gate signals can be supplied thereto. In contrast, a source or drain electrode 5014 functioning as a data line is shared by the transistors 5016 and 5017. Any of the above-described transistors can be used as appropriate as each of the transistors 5016 and 5017. Thus, a liquid crystal display device having high display quality and/or high reliability can be provided.

A first pixel electrode is electrically connected to the transistor 5016 and a second pixel electrode is electrically connected to the transistor 5017. The first pixel electrode and the second pixel electrode are separated. Shapes of the first pixel electrode and the second pixel electrode are not especially limited. For example, the first pixel electrode may have a V-like shape.

A gate electrode of the transistor 5016 is electrically connected to the gate wiring 5012, and a gate electrode of the transistor 5017 is electrically connected to the gate wiring 5013. When different gate signals are supplied to the gate wiring 5012 and the gate wiring 5013, operation timings of the transistor 5016 and the transistor 5017 can be varied. As a result, alignment of liquid crystals can be controlled.

Furthermore, a capacitor may be formed using a capacitor wiring 5010, a gate insulating film functioning as a dielectric, and a capacitor electrode electrically connected to the first pixel electrode or the second pixel electrode.

The pixel structure is a multi-domain structure in which a first liquid crystal element 5018 and a second liquid crystal element 5019 are provided in one pixel. The first liquid crystal element 5018 includes the first pixel electrode, a counter electrode, and a liquid crystal layer therebetween. The second liquid crystal element 5019 includes the second pixel electrode, a counter electrode, and a liquid crystal layer therebetween.

Note that a pixel circuit in the display device of one embodiment of the present invention is not limited to that shown in FIG. 14B. For example, a switch, a resistor, a capacitor, a transistor, a sensor, a logic circuit, or the like may be added to the pixel circuit shown in FIG. 14B.

[Organic EL Display Device]

FIG. 14C illustrates another example of a circuit configuration of the pixel. Here, a pixel structure of a display device using an organic EL element is shown.

In an organic EL element, by application of voltage to a light-emitting element, electrons are injected from one of a pair of electrodes included in the organic EL element and holes are injected from the other of the pair of electrodes, into a layer containing a light-emitting organic compound; thus, current flows. The electrons and holes are recombined, and thus, the light-emitting organic compound is excited. The light-emitting organic compound returns to a ground state from the excited state, thereby emitting light. Owing to such a mechanism, this light-emitting element is referred to as a current-excitation light-emitting element.

FIG. 14C illustrates an example of a pixel circuit. Here, one pixel includes two n-channel transistors. Note that the transistor 200 can be used as the n-channel transistors. Furthermore, digital time grayscale driving can be employed for the pixel circuit.

The configuration of the applicable pixel circuit and operation of a pixel employing digital time grayscale driving will be described.

A pixel 5020 includes a switching transistor 5021, a driver transistor 5022, a light-emitting element 5024, and a capacitor 5023. A gate electrode of the switching transistor 5021 is connected to a scan line 5026, a first electrode (one of a source electrode and a drain electrode) of the switching transistor 5021 is connected to a signal line 5025, and a second electrode (the other of the source electrode and the drain electrode) of the switching transistor 5021 is connected to a gate electrode of the driver transistor 5022. The gate electrode of the driver transistor 5022 is connected to a power supply line 5027 through the capacitor 5023, a first electrode of the driver transistor 5022 is connected to the power supply line 5027, and a second electrode of the driver transistor 5022 is connected to a first electrode (a pixel electrode) of the light-emitting element 5024. A second electrode of the light-emitting element 5024 corresponds to a common electrode 5028. The common electrode 5028 is electrically connected to a common potential line provided over the same substrate.

As each of the switching transistor 5021 and the driver transistor 5022, the transistor 490 can be used as appropriate. In this manner, an organic EL display device having high display quality and/or high reliability can be provided.

The potential of the second electrode (the common electrode 5028) of the light-emitting element 5024 is set to be a low power supply potential. Note that the low power supply potential is lower than a high power supply potential supplied to the power supply line 5027. For example, the low power supply potential can be GND, 0 V, or the like. The high power supply potential and the low power supply potential are set to be higher than or equal to the forward threshold voltage of the light-emitting element 5024, and the difference between the potentials is applied to the light-emitting element 5024, whereby current is supplied to the light-emitting element 5024, leading to light emission. The forward voltage of the light-emitting element 5024 refers to a voltage at which a desired luminance is obtained, and includes at least forward threshold voltage.

Note that gate capacitance of the driver transistor 5022 may be used as a substitute for the capacitor 5023 in some cases, so that the capacitor 5023 can be omitted. The gate capacitance of the driver transistor 5022 may be formed between the channel formation region and the gate electrode.

Next, a signal input to the driver transistor 5022 is described. In the case of a voltage-input voltage driving method, a video signal for turning on or off the driver transistor 5022 is input to the driver transistor 5022. In order for the driver transistor 5022 to operate in a linear region, voltage higher than the voltage of the power supply line 5027 is applied to the gate electrode of the driver transistor 5022. Note that voltage higher than or equal to voltage which is the sum of power supply line voltage and the threshold voltage V_(th) of the driver transistor 5022 is applied to the signal line 5025.

In the case of performing analog grayscale driving, a voltage higher than or equal to a voltage which is the sum of the forward voltage of the light-emitting element 5024 and the threshold voltage V_(th) of the driver transistor 5022 is applied to the gate electrode of the driver transistor 5022. A video signal by which the driver transistor 5022 is operated in a saturation region is input, so that current is supplied to the light-emitting element 5024. In order for the driver transistor 5022 to operate in a saturation region, the potential of the power supply line 5027 is set higher than the gate potential of the driver transistor 5022. When an analog video signal is used, it is possible to supply current to the light-emitting element 5024 in accordance with the video signal and perform analog grayscale driving.

Note that in the display device of one embodiment of the present invention, a pixel configuration is not limited to that shown in FIG. 14C. For example, a switch, a resistor, a capacitor, a sensor, a transistor, a logic circuit, or the like may be added to the pixel circuit shown in FIG. 14C.

In the case where the transistor 200 is used for the circuit shown in FIGS. 14A to 14C, the source electrode (the first electrode) is electrically connected to the low potential side and the drain electrode (the second electrode) is electrically connected to the high potential side. Furthermore, the potential of the first gate electrode may be controlled by a control circuit or the like and the potential described above as an example, e.g., a potential lower than the potential applied to the source electrode, may be input to the second gate electrode.

For example, in this specification and the like, a display element, a display device which is a device including a display element, a light-emitting element, and a light-emitting device which is a device including a light-emitting element can employ a variety of modes or can include a variety of elements. A display element, a display device, a light-emitting element, or a light-emitting device include at least one of the following, for example: an EL (electroluminescent) element (e.g., an EL element including organic and inorganic materials, an organic EL element, or an inorganic EL element), an LED (e.g., a white LED, a red LED, a green LED, or a blue LED), a transistor (a transistor which emits light depending on current), an electron emitter, a liquid crystal element, electronic ink, an electrophoretic element, a grating light valve (GLV), a plasma display panel (PDP), a micro electro mechanical system (MEMS), a digital micromirror device (DMD), a digital micro shutter (DMS), an interferometric modulator display (IMOD) element, an electrowetting element, a piezoelectric ceramic display and a display element using a carbon nanotube. Other than the above, display media whose contrast, luminance, reflectivity, transmittance, or the like is changed by electrical or magnetic effect may be included. Examples of display devices having EL elements include an EL display. Examples of a display device including an electron emitter include a field emission display (FED), an SED-type flat panel display (SED: surface-conduction electron-emitter display), and the like. Examples of display devices including liquid crystal elements include a liquid crystal display (e.g., a transmissive liquid crystal display, a transflective liquid crystal display, a reflective liquid crystal display, a direct-view liquid crystal display, or a projection liquid crystal display). Display devices having electronic ink or electrophoretic elements include electronic paper and the like.

A color layer (also referred to as a color filter) may be used in order to obtain a full-color display device in which white light (W) for a backlight (e.g., an organic EL element, an inorganic EL element, an LED, or a fluorescent lamp) is used. As the color layer, red (R), green (G), blue (B), yellow (Y), or the like may be combined as appropriate, for example. With the use of the color layer, higher color reproductivity can be obtained than in the case without the color layer. In this case, by providing a region with the color layer and a region without the color layer, white light in the region without the color layer may be directly utilized for display. By partly providing the region without the color layer, a decrease in luminance due to the color layer can be suppressed, and 20% to 30% of power consumption can be reduced in some cases when an image is displayed brightly. Note that in the case where frill-color display is performed using a self-luminous element such as an organic EL element or an inorganic EL element, elements may emit light of their respective colors R, G, B, Y, and W. The use of a self-luminous element allows a reduction in power consumption as compared to the case of using the color layer in some cases.

<Module>

A display module using a semiconductor device of one embodiment of the present invention is described below with reference to FIG. 15.

In a display module 8000 in FIG. 15, a touch panel 8004 connected to an FPC 8003, a cell 8006 connected to an FPC 8005, a backlight unit 8007, a frame 8009, a printed board 8010, and a battery 8011 are provided between an upper cover 8001 and a lower cover 8002. Note that the backlight unit 8007, the battery 8011, the touch panel 8004, and the like are not provided in some cases.

The semiconductor device of one embodiment of the present invention can be used for the cell 8006, for example.

The shapes and sizes of the upper cover 8001 and the lower cover 8002 can be changed as appropriate in accordance with the sizes of the touch panel 8004 and the cell 8006.

The touch panel 8004 can be a resistive touch panel or a capacitive touch panel and may be formed to overlap with the cell 8006. A counter substrate (sealing substrate) of the cell 8006 can have a touch panel function. A photosensor may be provided in each pixel of the cell 8006 so that an optical touch panel is obtained. An electrode for a touch sensor may be provided in each pixel of the cell 8006 so that a capacitive touch panel is obtained. An electrode for a touch sensor may be provided in each pixel of the cell 8006 so that a capacitive touch panel is obtained.

The backlight unit 8007 includes a light source 8008. The light source 8008 may be provided at an end portion of the backlight unit 8007 and a light diffusing plate may be used.

The frame 8009 may protect the cell 8006 and also function as an electromagnetic shield for blocking electromagnetic waves generated by the operation of the printed board 8010. The frame 8009 may function as a radiator plate.

The printed board 8010 has a power supply circuit and a signal processing circuit for outputting a video signal and a clock signal. As a power source for supplying power to the power supply circuit, an external commercial power source or a power source using the battery 8011 provided separately may be used. The battery 8011 can be omitted in the case of using a commercial power source.

The display module 8000 can be additionally provided with a member such as a polarizing plate, a retardation plate, or a prism sheet

<Electronic Device>

The semiconductor device of one embodiment of the present invention can be used for display devices, personal computers, or image reproducing devices provided with recording media (typically, devices which reproduce the content of recording media such as digital versatile discs (DVDs) and have displays for displaying the reproduced images). Other examples of electronic devices that can be equipped with the semiconductor device of one embodiment of the present invention are mobile phones, game machines including portable game consoles, portable data terminals, e-book readers, cameras such as video cameras and digital still cameras, goggle-type displays (head mounted displays), navigation systems, audio reproducing devices (e.g., car audio systems and digital audio players), copiers, facsimiles, printers, multifunction printers, automated teller machines (ATM), and vending machines. FIGS. 18A to 18F illustrate specific examples of these electronic devices.

FIG. 16A illustrates a portable game console including a housing 901, a housing 902, a display portion 903, a display portion 904, a microphone 905, a speaker 906, an operation key 907, a stylus 908, and the like. Although the portable game console in FIG. 16A has the two display portions 903 and 904, the number of display portions included in a portable game console is not limited to this.

FIG. 16B illustrates a portable data terminal including a first housing 911, a second housing 912, a first display portion 913, a second display portion 914, a joint 915, an operation key 916, and the like. The first display portion 913 is provided in the first housing 911, and the second display portion 914 is provided in the second housing 912. The first housing 911 and the second housing 912 are connected to each other with the joint 915, and the angle between the first housing 911 and the second housing 912 can be changed with the joint 915. An image on the first display portion 913 may be switched depending on the angle between the first housing 911 and the second housing 912 at the joint 915. A display device with a position input function may be used as at least one of the first display portion 913 and the second display portion 914. Note that the position input function can be added by providing a touch panel in a display device. Alternatively, the position input function can be added by provision of a photoelectric conversion element called a photosensor in a pixel portion of a display device.

FIG. 16C illustrates a laptop personal computer including a housing 921, a display portion 922, a keyboard 923, a pointing device 924, and the like.

FIG. 16D illustrates an electric refrigerator-freezer including a housing 931, a door for a refrigerator 932, a door for a freezer 933, and the like.

FIG. 16E illustrates a video camera including a first housing 941, a second housing 942, a display portion 943, operation keys 944, a lens 945, a joint 946, and the like. The operation keys 944 and the lens 945 are provided for the first housing 941, and the display portion 943 is provided for the second housing 942. The first housing 941 and the second housing 942 are connected to each other with the joint 946, and the angle between the first housing 941 and the second housing 942 can be changed with the joint 946. Images displayed on the display portion 943 may be switched in accordance with the angle between the first housing 941 and the second housing 942 at the joint 946.

FIG. 16F illustrates an automobile including a car body 951, wheels 952, a dashboard 953, lights 954, and the like.

<Electronic Device with Curved Display Region or Curved Light-Emitting Region>

Electronic devices with a curved display region or a curved light-emitting region, which are embodiments of the present invention, are described below with reference to FIGS. 17A1, 17A2, 17A3, 17B1 and 17B2. Here, information devices, in particular, portable information devices (portable devices) are described as examples of the electronic devices. The portable information devices include, for example, mobile phone devices (e.g., phablets and smartphones) and tablet terminals (slate PCs).

FIG. 17A1 is a perspective view illustrating the outward form of a portable device 1300A. FIG. 17A2 is a top view illustrating the portable device 1300A. FIG. 17A3 illustrates the portable device 1300A in use.

FIGS. 17B1 and 17B2 are perspective views illustrating the outward form of a portable device 1300B.

FIGS. 17C1 and 17C2 are perspective views illustrating the outward form of a portable device 1300C.

<Portable Device>

The portable device 1300A has one or more functions of a telephone, email creating and reading, a notebook, information browsing, and the like.

A display portion of the portable device 1300A is provided along plural surfaces. For example, the display portion may be provided by placing a flexible display device along the inside of a housing. Thus, text data, image data, or the like can be displayed on a first region 1311 and/or a second region 1312.

For example, images used for three operations can be displayed on the first region 1311 (see FIG. 17A1). Furthermore, text data and the like can be displayed on the second region 1312 as indicated by dashed rectangles in the drawing (see FIG. 17A2).

In the case where the second region 1312 is on the upper portion of the portable device 1300A, a user can easily see text data or image data displayed on the second region 1312 of the portable device 1300A while the portable device 1300A is placed in a breast pocket of the user's clothes (see FIG. 17A3). For example, the user can see the phone number, name, and the like of the caller of an incoming call, from above the portable device 1300A.

The portable device 1300A may include an input device or the like between the display device and the housing, in the display device, or over the housing. As the input device, for example, a touch sensor, a light sensor, or an ultrasonic sensor may be used. In the case where the input device is provided between the display device and the housing or over the housing, a touch panel may be, for example, a matrix switch type, a resistive type, an ultrasonic surface acoustic wave type, an infrared type, electromagnetic induction type, or an electrostatic capacitance type. In the case where the input device is provided in the display device, an in-cell sensor, an on-cell sensor, or the like may be used.

Note that the portable device 1300A can be provided with a vibration sensor or the like and a memory device that stores a program for shifting a mode into an incoming call rejection mode based on vibration sensed by the vibration sensor or the like. Thus, the user can shift the mode into the incoming call rejection mode by tapping the portable device 1300A over his/her clothes to apply vibration.

The portable device 1300B includes a display portion including the first region 1311 and the second region 1312 and a housing 1310 that supports the display portion.

The housing 1310 has a plurality of bend portions, and the longest bend portion in the housing 1310 is between the first region 1311 and the second region 1312.

The portable device 1300B can be used with the second region 1312 provided along the longest bend portion facing sideward.

The portable device 1300C includes a display portion including the first region 1311 and the second region 1312 and the housing 1310 that supports the display portion.

The housing 1310 has a plurality of bend portions, and the second longest bend portion in the housing 1310 is between the first region 1311 and the second region 1312.

The portable device 1300C can be used with the second region 1312 facing upward.

Note that contents that are not specified in any drawing or text in the specification can be excluded from one embodiment of the invention. Alternatively, when the range of a value that is defined by the maximum and minimum values is described, part of the range is appropriately narrowed or part of the range is removed, whereby one embodiment of the invention excluding part of the range can be constructed. In this manner, it is possible to specify the technical scope of one embodiment of the present invention so that a conventional technology is excluded, for example.

As another specific example, a description “a film is an insulator” is given to describe properties of a material. In that case, for example, it can be specified that the case where the insulator is an organic insulator is excluded from one embodiment of the invention. For example, it can be specified that the case where the insulator is an inorganic insulator is excluded from one embodiment of the invention. For example, it can be specified that the case where the film is a conductor is excluded from one embodiment of the invention. For example, it can be specified that the case where the film is a semiconductor is excluded from one embodiment of the invention.

As another specific example, the description of a stacked structure, “a film is provided between an A film and a B film” is given. In that case, for example, it can be specified that the case where the film is a stacked film of four or more layers is excluded from the invention. For example, it can be specified that the case where a conductor is provided between the A film and the film is excluded from the invention.

Note that in this specification and the like, it might be possible for those skilled in the art to constitute one embodiment of the invention even when portions to which all the terminals of an active element (e.g., a transistor or a diode), a passive element (e.g., a capacitor or a resistor), or the like are connected are not specified. In other words, one embodiment of the invention can be clear even when connection portions are not specified. Further, in the case where a connection portion is disclosed in this specification and the like, it can be determined that one embodiment of the invention in which a connection portion is not specified is disclosed in this specification and the like, in some cases. In particular, in the case where the number of portions to which the terminal is connected might be plural, it is not necessary to specify the portions to which the terminal is connected. Therefore, it might be possible to constitute one embodiment of the invention by specifying only portions to which some of terminals of an active element (e.g., a transistor or a diode), a passive element (e.g., a capacitor or a resistor), or the like are connected.

Note that in this specification and the like, it might be possible for those skilled in the art to specify the invention when at least the connection portion of a circuit is specified. Alternatively, it might be possible for those skilled in the art to specify the invention when at least a function of a circuit is specified. In other words, when a function of a circuit is specified, one embodiment of the invention can be clear. Furthermore, it can be determined that one embodiment of the invention whose function is specified is disclosed in this specification and the like. Therefore, when a connection portion of a circuit is specified, the circuit is disclosed as one embodiment of the invention even when a function is not specified, and one embodiment of the invention can be constituted. Alternatively, when a function of a circuit is specified, the circuit is disclosed as one embodiment of the invention even when a connection portion is not specified, and one embodiment of the invention can be constituted.

Note that in this specification and the like, a content described in at least a diagram (which may be part of the diagram) is disclosed as one embodiment of the invention, and one embodiment of the invention can be constituted. Therefore, when a certain content is described in a diagram, the content is disclosed as one embodiment of the invention even when the content is not described with a text, and one embodiment of the invention can be constituted. In a similar manner, part of a diagram, which is taken out from the diagram, is disclosed as one embodiment of the invention, and one embodiment of the invention can be constituted. The embodiment of the invention is clear.

This application is based on Japanese Patent Application serial no. 2014-102319 filed with Japan Patent Office on May 16, 2014, the entire contents of which are hereby incorporated by reference. 

What is claimed is:
 1. A manufacturing method of a semiconductor substrate comprising: forming a first oxide semiconductor over a first substrate; forming a first insulator over the first oxide semiconductor; injecting an ion into a region of the first oxide semiconductor through the first insulator; bonding a surface of the first insulator over the first substrate to a surface of a second insulator over a second substrate; performing a heat treatment in a state where the first substrate and the second substrate are bonded each other; and separating the first substrate from the second substrate along the region of the first oxide semiconductor to form a second oxide semiconductor over the second substrate.
 2. The manufacturing method of a semiconductor substrate, according to claim 1, wherein the first oxide semiconductor has a single crystal structure.
 3. The manufacturing method of a semiconductor substrate, according to claim 1, wherein the ion is a hydrogen ion.
 4. The manufacturing method of a semiconductor substrate, according to claim 1, wherein the bonding is performed by combining the surface of the first insulator with the surface of the second insulator.
 5. A manufacturing method of a semiconductor substrate comprising: forming a first oxide semiconductor over a first substrate; forming a first insulator over the first oxide semiconductor; injecting an ion into a region of the first oxide semiconductor through the first insulator; bonding a surface of the first insulator over the first substrate to a surface of a second insulator over a second substrate, the second substrate comprising a semiconductor element and the second insulator over the semiconductor element; performing a heat treatment in a state where the first substrate and the second substrate are bonded each other; and separating the first substrate from the second substrate along the region of the first oxide semiconductor to form a second oxide semiconductor and the semiconductor element over the second substrate.
 6. The manufacturing method of a semiconductor substrate, according to claim 5, wherein the first oxide semiconductor has a single crystal structure.
 7. The manufacturing method of a semiconductor substrate, according to claim 5, wherein the ion is a hydrogen ion.
 8. The manufacturing method of a semiconductor substrate, according to claim 5, wherein the bonding is performed by combining the surface of the first insulator with the surface of the second insulator.
 9. A manufacturing method of a semiconductor substrate comprising: forming a first oxide semiconductor over a first substrate; forming a first insulator over the first oxide semiconductor; injecting an ion into a region of the first oxide semiconductor through the first insulator; bonding a surface of the first insulator over the first substrate to a surface of a second insulator over a second substrate; performing a heat treatment in a state where the first substrate and the second substrate are bonded each other; separating the first substrate from the second substrate along the region of the first oxide semiconductor to form a second oxide semiconductor over the second substrate; and forming a semiconductor element including the second oxide semiconductor.
 10. The manufacturing method of a semiconductor substrate, according to claim 9, wherein the first oxide semiconductor has a single crystal structure.
 11. The manufacturing method of a semiconductor substrate, according to claim 9, wherein the ion is a hydrogen ion.
 12. The manufacturing method of a semiconductor substrate, according to claim 9, wherein the bonding is performed by combining the surface of the first insulator with the surface of the second insulator.
 13. A manufacturing method of a semiconductor substrate comprising: forming a first oxide semiconductor over a first substrate; forming a first insulator over the first oxide semiconductor; injecting an ion into a region of the first oxide semiconductor through the first insulator; bonding a surface of the first insulator over the first substrate to a surface of a second insulator over a second substrate, the second substrate comprising a first semiconductor element and the second insulator over the first semiconductor element; performing a heat treatment in a state where the first substrate and the second substrate are bonded each other; separating the first substrate from the second substrate along the region of the first oxide semiconductor to form a second oxide semiconductor and the first semiconductor element over the second substrate; and forming a second semiconductor element including the second oxide semiconductor.
 14. The manufacturing method of a semiconductor substrate, according to claim 13, wherein the first oxide semiconductor has a single crystal structure.
 15. The manufacturing method of a semiconductor substrate, according to claim 13, wherein the ion is a hydrogen ion.
 16. The manufacturing method of a semiconductor substrate, according to claim 13, wherein the bonding is performed by combining the surface of the first insulator with the surface of the second insulator. 